Question

The probability that a person catches a cold during the cold and flu season is 0.4. assume that 10 people are chosen at random. what is the probability that exactly four of them will catch a cold

Answer 1

From the information given;
P(cold) = 0.4
P(no cold) = 1-0.4 = 0.6

The number of ways of selecting 4 from 10 = 10C4 = 210

Probability that the 4 selected with catch a cold:

P(4 will catch cold) = (10C4)*P(cold)^4*P(no cold)^6 =  210*0.4^4*0.6^6 = 0.2508